Pump for fluid and semi-fluid materials such as plaster and the like



y 1956 E. A. VON SEGGERN 2,747,510

PUMP FOR FLUID AND SEMI-FLUID MATERIALS SUCH AS PLASTER AND THE LIKE 4Sheets-Sheet 1 Filed Jan. 12, 1952 H INVENTOR.

[RA/Ear A. VON Jeaasezv Jeremy May 29, 1956 E. A. VON SEGGERN PUMP FORFLUID AND SEMI-FLUID MATERIALS SUCH AS PLASTER AND THE LIKE 4Sheets-Sheet 2 Filed Jan. 12, 1952 INVENTOR. ERNEsT .14. von 656650 mm.W m

Q U Q y 9, 1956 E. A. VON SEGGERN 2,747,510

PUMP FOR FLUID AND SEMI-FLUID MATERIALS SUCH AS PLASTER AND THE LIKEFiled Jan. 12, 1952 4 Sheets-Sheet 3 INVENTOR. [R/wssr 14. VOIVJ's-6662M States Patent 6 PUD/ P FOR FLUID AND SEMI-FLUID MATERIALS SUCHAS PLASTER AND THE LIKE Ernest A. von Seggern, Burbank, Califi, assignorto Soundrive Pump Company, Hollywood, Calif., a corporation ofCalifornia Application January 12, 1952, Serial No. 266,226

22 Claims. (Cl. 103-44) This invention relates to pumps for pumpingliquids, and particularly to pumps for pumping viscous, abrasivematerials which solidify with time. It relates specifically to pumps forpumping semi-fluid mixtures of pulverized solids and liquids which donot readily remain mixed in uniform proportions but tend to separatewhen being pumped or handled. Such mixtures may include severaldifferent solid materials in various states of pulveri'zation, incombination with one or more fluids as a vehicle. Examples of suchmixtures are interior plaster and external stucco as used in thebuilding trades and similar classes of cements and aggregates insuspension in water.

There are certain physical properties possessed by this class ofsemi-liquids that make them practicallyimpossible to pump by any knownprior art device. The material is: (1) viscous, (2) abrasive, (3)non-homogeneous, (4) compressible, (5) unstable in mixture, (6)self-hardening with time.

It is accordingly a general object of the present invention to provide apump which will handle fluids or semifluids having the above-namedproperties singly or in combination.

A further object is to provide a positive displacement pump capable ofproducing high discharge pressures in which the flow of liquid throughthe pump is slow and non-turbulent.

Another object is to provide a pump in which all the parts subjected tothe abrasive action of the fluid are either made of rubber or rubbercoated, or of equivalent flexible or elastic material capable ofwithstanding abrasion. 7

A further object is to provide a pump having a large compression ratio,that is, a large change'in displacement during the working cyclerelative to the volume of the material acted upon.

Another object is to provide a pump in which substantially no pressuregradients or inertia forces are established in the fluid which tend toseparate materials having different densities, or different size, ordifferent hardness, or diiferent viscosity.

Another object is to provide a pump having a small and substantiallysmooth bore therethrough'at all points in which the flow of material issufliciently fast and uniform so that at no point is the accumulation ofstatic material possible.

A furtherobject is to'provide a pump of the above class which is simplein design, positive in action, and which will'not readily deteriorate orget out of order.

The pump of the invention, in its most elementary form, employs aflexible'tube, fitted with suitable valves at its intake and dischargeends. A means is provided for alternately contracting and expanding thecross-sectional area of this flexible tube, and comprises preferably ameans for alternately raising and reducing the pressure on a hydraulicbody which is arranged in a pressure transmissive relationship with theoutside of the tube. On each pressure rise, the tube contracts, and oneach pressure reduction, atmospheric pressure inside the tube causes anexpansion. On each such expansion, the fluid or semi-fluid material tobe pumped is drawn into the tube through its intake valve, and on eachcontraction, the material is evacuated through the discharge valve. Thisunit as thus broadly described provides a conduit of smooth interior,with a minimum of bends, turns, corner's or pockets, so that the pump isself-purging. That is to say, the material to be pumped is all movedalong the tube, with a minimum tendency for any of the material tostagnate in corners, pockets, and the like. The unit as thus broadlydescribed also has the feature of high compression ratio, or in otherwords, high ratio of displacement volume to total volume, with theresult that a high ratio of flow rate to volume is achieved, and again,the tendency for stagnation in corners, bends or pockets is minimized.This high compression ratio also makes the pump self-priming.

In a more advanced form of the invention, two or more such pumpunits areused in a series multi-stage arrangement. Here, a longer pump isachieved, with corresponding addition of pumping effort. It will be seenthat this multistage series arrangement, if the pumps are worked inunisomwill increase the displacement over the single type unit, withoutrequiring that the multiple units discharge into a header, as is commonwith multiple cylinder pumps. In other words, the pump capacity isincreased, While still keeping a single uniform flow conduit.

In a multiple-stage pump, the pressure per stage, required for unitdischarge, can be reduced by synchronizing the successive stages to givewhat may be referred to as polyphase operation. Here, the contractiveand expansive movements of the stages occur with a definite phasediiference. Taking a typical two-phase, system for simple illustration,the flexible tube of the second stage is expanded while the flexibletube of the first stage is contracted, and vice-versa. The stages inthis case are seen to operate with 180 phase difference. A threestagepump may be operated with phase difference between stages, and so on. Itwill be seen that, considering the long flexible conduit running throughthe successive stages, alternate waves of contraction and expansiontravel along the conduit, forcing the fluid or semi-fluid material alongin a manner somewhat analogous to the peristaltic wave movement thatoccurs in the animal intestine.

In a preferred form of such a polyphase pump, a very important furtherimprovement is achieved by designing successive stages to havesuccessively decreasing displacement. The pump as described hereinabovedischarges the pumped materialin surges or pulses. This pulsing efiectis very greatly reduced by the feature of successive reductions indisplacement in the successive pump stages. For simple illustration,avtwo-stage polyphase pump will be considered, with the two stagesoperating with phase difference, and with the first stage designed tohave double the displacement of the second. For convenience, let it beassumed that the second stage pumps one unit volume on each contractionof its flexible tube, while the first pumps two units of volume on eachcontraction. On the discharge (contraction) strokeof the first stage,two units of volume are discharged into the second stage. The secondstage is then undergoing its intake or expansion stroke, and it fillswith one of said unit volumes, while the other passes entirely throughthe second stage and is discharged therefrom. Then, on the intake strokeof the first stage, the first stage fills again with two unit volumes;while the second stage, then undergoing its contraction or compressionstroke, discharges one unit volume. Thus the second stage discharges oneunit volume on each of'its strokes, so that discharge is continuous-This discharge, while it may be called continuous, is still, however,possessed ofa Patented May 29, 1956 pulsating character, and a laterdescribed accumulator means is preferably employed to give the outflow anearly uniform flow characteristic.

- Further details, features and accomplishments of the invention will bedescribed or appear in the course of the following detailed descriptionof an illustrative embodimentthereof, reference being had to theaccompanying drawings, wherein:

. Figure 1 is a side elevational view of a pump in accord ance with theinvention, parts of theexterior casing and framework being broken away;

Figure 2 is an end elevational view, looking from the right of the pumpof Figure 1;

Figure 3 is a perspective view of the motive power unit of the pump ofFigures 1 and 2;

Figure 4 is a vertical'longitudinal section taken on the line 4-4 ofFigure 2;

a Figure 5 is a cross-sectional view taken on line 5-5 of Figure 4; Y

Figure 6 is a section taken on line 6-6 of Figure 4;

Figure 7 is a section taken on line 77 of Figure 4;

Figure 8 is a section taken on line 3-8 of Figure 4;

Figure 9 is a section taken on line 9-9 of Figure 4;

Figure 10 is a section taken on line 10-10 of Figure 4;

Figure 11 is a section similar to a portion of Figure 4 but showinganother position in the operating cycle of the pump;

Figure 12 is a diagrammatic view of a three-cycle form of the pump; and

Figure 13 is a diagram of phase relations occurring in the pump ofFigure 12.

In Figures 111 of the drawings, a multistage polyphase pump,'in thiscase a two-stage type, has been shown for illustrative purposes, andcomprises in this instance a first stage I, and a second stage II, thefirst being hopper fed, and the second being arranged in series with thefirst, so that its intake directly receives the discharge from thefirst. The two stages are characterized by a long, relatively smoothconduit C extending therethrough, suitably valved, as describedhereinafter, and principally made up of serially connected flexibletubes'Tl and T2 for the first and second stages, respectively. Liquidfilled chambers C1 and C2, including contractive and expansivediaphragms Dl and D2, surround the two flexible tubes.

T1' and T2, respectively' They afford a simple and presently preferredembodiment of means for alternately increasing and reducing the externalpressure on the flexible tubes and thereby alternately contracting andexpanding the same to give the novel multistage pumping Further, asingle frame by means of angle members 17. p

The illustrative pump is of a two-stag type; though-v as alreadymentioned, a single stage may be employed, and also additional stagesmay be provided if desired.

The present pump accordingly includes a first stage or unit I and asecond stage or unit II. These pump units have tubular housings,including a rigid stationary and axially movable housing sections 22 and23, respectively in the case of stageI, and 24 and 25, respectively inthe case of stage II, to house the aforementioned smooth conduit C. Theaxially movable sections 23 and 25 are interconnected as later describedto move 'in unison.

by the aforementioned sub-frame members 16,'in the manner clearly shownin Figure 6. As there shown, the

members 16 are formed with half-round seats to receive the lower halvesof said housing sections, the other halves being supported by half-roundstraps 26 secured to members 16 as by screws 26a.

The pump includes a hopper 30, flange connected at the bottom, as at 31,to a tubular neck 32 extending upwardly from a tubular housing member 33connected to the intake end of the aforesaid stationarily mountedhousing member 22 of first pump unit I. This housing member 22 hastowards its intake end a flared portion 50, to which is joined anoutwardly offset box portion 51, terminating in an external flange 52.This flanged end abuts a flange. 53,011 the end of the tubular housingmember 33, and the parts are held in assembly by means of bolts 54passing through flange 53 and through a retainer ring 55 engaging inback of flange 52.

Contained within tubular member 33 is a snugly fitted plug 56, securedin position by a clamp screw 57 mounted in a pivoted frame 58. This plughas a large fluid passage 60 communicating at one end with the passage61in neck 32., which in turn communicates with hopper'3tl. At its otherend, passage 60 communicates with a port 62 in a valve seat ring 63screwthreadedly joined to the inner end of plug 56. A second ring 64 isscrewthreadcdly joined to ring 63, and the tworings cooperate to definea tapered valve seat 65, and also an annular seat for a rubber sealingring 66 which is partially exposed through tapered seat 65. A valve ball67 seats against this valve seat and sealing ring, being normally heldclosed by a spiral spring 68 seated in an annular groove formed withinring 64, as shown. The aforementioned plug 56 is readily removable fromthe assembly by loosening screw 57 and swinging frame 58 out of the way,and serves as a means for readily removing the valve for inspection or,repair.

A retainer ring 7%) received inside box 51 engages flange 53 and has aninwardly extending annular flange 71 overhanging and engaging theprojecting end of valve seat ring 64. Flexible tube T1, preferablycomposed of rubber or equivalent elastic material, is disposed in aconcentric position inside tubular housing member 22, being of adiameter to provide an annular space 73 between said tube and housingmember 22. At the lefthand or intake end of the pump unit, an endportion of this rubber tube is clamped and sealed between outer andinner conical clamping and sealing rings 74 and '75, respectively, theformer having an end flange 76 screwed into retainer ring 70, and thelatter being shaped at its forward or large end to slide snugly insideflange '76. while forming with member 74 a conical channel within whichthe end portion of the rubber tube is snugly clamped when the two ringshave been moved into assembly. 7 a

The righthandor discharge end of rubber tube Tl is clamped and sealed atthe righthand end of the afore mentioned axially movable housing member23 between outer and inner clamping rings 82 and 33, respectively. Theouter ring 82 has converging conical surfaces 84 and 85, forming an apexof just slightly less diameter than the outside diameter of rubber tubeTl. The rubber tube T1 is accordingly constricted slightly by engagementwith this apex, but its end portion is expanded Slightly, into a conicalor flared shape, by being gripped between the conical surface 85 and aparallel conical surface 87 on the inner ring 33. The latter has at itsend an external The inside surface of ring 83 converges toward the dis,The stationary sections 22 and 24 are rigidly supported A charge end'ofthe pump, giving a converging discharge passageway 89. The two clampingringsSZ and 83- are secured in assembly by means of a retainer ring 9t?screwed on'over outside clamping ring 82 and siidable inside the bore ofhousing member 23. This ring 9!).

has a portion normally projecting from the end of housing member 23, andwhich is axially positioned by means arrests of a positioning ring 92threaded thereto and adapted to engage the end of housing member 23. Aswill be seen, the retainer ring. 96 also has wall portion 93 whichengages the ends of both of the clamping. rings to secure them properlyin assembly.

The two housing sections 22 and 23 of the pump are joined by a flexiblediaphragm. member D1 comprising in this instance an annulus of generallyU or horseshoe shape in section. It resembles, and may actually be, anordinary rubber tire casing. The inner edges or beads of this tire-likediaphragm engage the two housing members 22 and 23 near the confrontingends thereof and each edge is clamped between an inner annular checkplate 96, shaped to conform to its inner periphery, and screwthreadedlymounted on the end of the corresponding housing tube, and a pair ofouter clamping rings 97 and 98 shaped to conform to its outer periphery,the former being screwthreaded to the outside of the latter. Theclamping rings 98 are slidabl-y mounted on the tubular housing members,and are set up by means of rings 99 threaded onto the housing members.The clamping ring 97 is capable of adjustment relative tothe ring 98',and is set up or locked by means of locking ring 100 screwed onto ring98.

The right hand end or extremity 80 of housing part 23 is enlarged and ofsquare cross section, and secured to this extremity 86 is a hollow blockunit 105' serving both as a means for interconnecting: and reciprocatingthe movable housing members 23' and 25, and also as a housing containingan intake check valve for the sec ond pump unit 21. This unit 105includes 'a square frame 106 which abuts squared extremity 80 of housingsection 23, and surrounds the positioning ring 92. As shown in Figure 8,the unit 105 also includes' two ver-- tical side plates 107 whose edgesabut the edges of frame 106. As shown in Figure 4 it also includesaplate or frame 168 which engages the opposite edges of side plates 107,and also abuts the squared extremity 140 of second stage movable housingsection 25. The members 106, 107' and 168 will be seen to form a box,open at top and bottom, and the inside surface of plate 108 is slantedto provide a tapered seat for a complementary tapered valve body 110'.The latter has a fl'uid passageway 111 controlled by check valve ball112. The ball 112 is provided with seat ring 113 (Figure 7) screwed intothe front face of plug 110, and seats on saidring and on a rubbersealring 114 lodged in a recess formed between said seat ring and theadjacent surface of'memher 110*. The opening of seat ring 113 alignswith the opening in retainer ring 90 and also with the end of dischargepassageway 89 of pump unit- 20. Beyond seat ring 113, fluid passageway111- has a diverging section 120, and then a converging section 121, theend of the latter aligning with port 122 in wall 108 (Figure 7).Spring'124 for valve ball 112 is lodged in a seat formed at the apex ofthe fluid passageway through plug 1'10, as clearly shown.

The valve body 110 is secured in position by means of a bar 130 securedto its upper edge, and hold-down screws 131 threaded into side plates107 (Figure 8), the screws 131. having intermediate flanges 132 receivedin notches formed in the two ends of the bar 130,, all as clearly shownin Figure 8. it will be seen that operation of the screws- 131 serveseither to secure the valve body tightly in position in its box, or toforce the valve body upwardly there from. The latter operation is ofadvantage in that the valve body may otherwise tend to become tightlywedged in place after a period of use.

Long screws 141 extend through the flanges afforded by the squaredextremities 80' and 140' of the movable housing sections 23 and 25' ofthe first and second pump stages, passing through the square ring106,.the side plates 107, and the wall 108, thus tying said memberstogether in rigid assembly.

Flexible tube T2, preferably rubber, or the equivalent, is disposed in aconcentric position inside the housing sections 24 and 25 of pump unitII, an annular space 146 being provided between said tube and thehousing members 24 and- 25. At the lefthand or intake end of the secondpump unit, anend portion of the tube is clamped and sealed between outerand inner conical clamping rings 147' and 148,. which are generally likethe corresponding clamping rings 74 and at the intake end of the firstpump unit.

Clamping ring 147 is received snugly inside the end portion of housingmember 25, its extremity beingscrewthreaded for engagement inside aretainer ring 149 seated inside the end of housing member 140, saidretainer ring having an. inwardly extending annular flange abutting theend of clamping ring 147 and engaging an external anular flange 150formed around the exterior of clamping. ring 143, the flange 150 seatinginside the conical surface of ring 147, as shown. Theendportion of therubber tube is thus clamped tightly and sealed between the adjacentconical surfaces of the two clamping rings 147 and 148, and the ring 148has a fluid passage 152 which is flush at one end with the port 122 andat the other with the interior surface of the tube T2.

At theopposite end, the' rubber tube T2 is clampedand sealed betweenouter and inner clamping rings and'1'61, respectively, the former havingconical surfaces 162- and- 163- form-ing an apex of just slightly lessdiam eter than the normal outside diameter of sleeve 145. The rubbertube T2 is accordingly constricted slightly by engagement with thisapex,but its end portion is expanded slightly, into a conical or flaredshape, by being gripped between the conical surface 163 and a conicalsurface onthe outside of inner clamping ring 161. The latter has at itsend an external annular flange 165 which seats inside the conicalsurface 163 of the outer ring, leaving a conical channel of properdimensions to tightly grip' the end portion of the rubber tube. Adischarge fitting flange-connected to the discharge end of housingmember 24 has a fluid passage which is flush with the fluid passagethrough clamping ring 161 and this fitting 170 includes an internallythreaded boss 171 adapted for coupling to a suitable delivery pipe orhose, not shown. The two clamping rings 1'69 and 161 are secured inassembly with one another by means of a retainer ring 172' screwed onover outsideclamping. ring 160 and slidable inside the bore of housingmember 24, this retainer ring 172 including an internal annular flange173 at its rearward endwhich engages behind the flange 165 to secure theparts in assembly; A positioning ring 175 screwed onto the end ofretainer ring 172 and received between a counterbore sunk into' the endof housing member 24 and an annular channel formed in fitting 1 70secures the clamping ring assembly 160, 161 rigidly to the discharge endof the pump.

The two housing sections 24 and 25 of second pump unit II are joined byflexible diaphragm D2, similar tothe diaphragm D1 of the firstd'escribedpump unit, and again comprising, in this instance, an annulus ofgenerally U or horseshoe shape in section, resembling an ordinary rubbertire casing, which in practice it may actually be. The inner edges orbeads of this tire-like diaphragm engage the two housing members 24 and25' near the confronting ends thereof and each is confined between aretainer ring 181 screwed onto the end of the corresponding pump andhousing member, and a clamping ring 182 slidable on the housing memberand set up by a retainer ring 183 screwthreaded onto the housing member,as at 184. Attention is at this time called to the fact that theflexible diaphragm D2 is internally supported by rings 181 having.outside diameters substantially less than the outside diameters of thecorresponding plates or rings- 96 which clamp the insides of theflexible diaphragm D1 of the first pump unit-. In practice, the areaincluded within the outside periph- 7 7 cries of rings 181 is made to beapproximately half the area included within the outside peripheries ofrings 96, giving the second pump unit half the effective displacement ofthe first unit.

As a preferred but optional feature, the flexible diaphragm D2 isspring-clamped between two dished clamping rings 199, which rings areconnected for movement toward and from one another by means of longbolts 191, compression springs 192 being placed on the bolts at one end,in a manner to, urge the two clamping plates 190 toward one another, andso tend to compress the diaphragm. This device functions to smooth outripples in the delivery rate from the pump, in a manner to be explainedhereinafter.

The pump is provided with sheet metal side walls 193 rising from frame10, the forward edges of which are connected to triangular front plates194 which follow the contour of the aforementioned hopper 30 and may bewelded or otherwise secured thereto. Rising from opposite edges of frame10 are channel members 195,

which join with the rearward edges of side walls 193, and a horizontalrock shaft 196 extending between and pivotally mounted on said channels195 carries a supporting frame 197 for electric drive motor M. In thepresent embodiment, the machine has been provided with an aircompressor, driven by the same electric motor M that powers the pump,such air compressor being used to provide a source of compressed air foruse in spraying or delivering the plaster or other material pumped bythe pump of the invention. Such air compressor has been shown at A,mounted on the same framework 197 that carries the electric motor, andbelt Connected to said motor as indicated at 198. It is to beunderstood, however, that this air compressor forms no part of thepresent invention and has only been illustrated as it forms a part ofthe present embodiment of the invention.

The shaft of motor M has a known type of springactuated variablediameter V-pulley 200, connected by belt 201 to a pulley 292 whichdrives reduction gear unit 203. Rocking movement of motor M and itsshaft accomplished by adjustment of rock shaft 196 shifts the beltrunning on the pulley 200 either toward or away from the axis of themotor shaft, thereby varying the effective diameter of the pulley, andhence the speed of drive, in a manner well known and unnecessary toillustrate herein. Such rocking adjustment of shaft 196 is accomplishedthrough an arm tightly mounted on the rock shaft, to which is connected,by a ball and socket joint 205, the end of an adjustment shaft 206 whichis screwthreadcd in a bracket member 287 secured to the hopper 39, theshaft 2G6 having a manually operating crank 209 on its end. Operation ofthis crank then moves the shaft 206 in an axial direction, and so swingsarm 294, rock shaft 196, and therefore the motor M, thereby effectingvariation in the speed of drive of the pump.

The power take-oft" shaft from reduction gear unit 203 carries crank210, connected by connecting rod 211 to one arm 212 of a bell crank 213.This bell crank includes a shaft or axle 214, pivotally mounted to subframe 14, and provided with a pair of upwardly extending arms 216 whichare pivotally connected at their upper ends to trunnions 217 extendingoppositely from the side plates 107 of the aforementioned central driveunit 105. Operation of drive motor 41 thus results in oscillation ofbell crank 213, whose upwardly reaching arms 216 oscillate the member195 rigidly connected between the two ends of the two pump units in adirection axially of the pumps. The fact that the driving connectionsbetween the bell crank arms 216 and the drive unit 105 travel in an areabout the axis of the bell crank, is of no significance since the entirecentral section of the pump, between the two flexible diaphragms D1 andD2, is flexibly mounted and can move a short 8 distance up and downalong with its axial translation without any difiiculty whatsoever.

In the operation of the pump, therefore, the pump drive unitreciprocates in a direction axially of tubes T1 and T2, carrying with itthe two movable housing sections 80 and of the two pump units. It willbe seen that in this operation, the portions of chambers C1 and C2defined by the diaphragms D1 and D2 are alternately compressed andexpanded, it being noted that when one diaphragm chamber is compressedthe other is expanded, and vice versa. The stroke of the reciprocatingparts is made such that the inner clamping members 96, in the case ofdiaphragm D1, and 181, in the case of diaphragm D2, do not quite engageone another at the extreme limit of compression.

At the time of assembly of the pump, the chambers Cl. and C2, within thediaphragms D1 and D2 and the tubular pump housings, outside of therubber tubes T1 and T2, are entirely filled with-a suitable liquid, suchas water. This is easiest accomplished by submerging the tubular housingsections, such as 22 and 23, together with the interconnectingdiaphragm, in water, the rubber tube and its end mountings beingremoved. To fill the diaphragm, a flexible tube can be inserted, andwith its end reaching to the high point of the diaphragm, suctionapplied to the tube will remove the air and permit complete filling.With the housing still submerged, the rubber tube, together with its endmountings, is inserted from the lefthand end of the housing, and theretainer ring 92 screwed in place. Suitable seals are provided, asindicated in the drawings, so that the assembly can then be removed fromthe water in which it has been submerged, and the',water, will then notleak from the chamber C1. A similar and entirely evident operation isemployed to fill the chamber C2 of the second stage.

The change in volume. of the space inside each diaphragm, due to thealternate compression and expansion as described hereinabove, istransmitted to the rubber tube by the water enclosed within thediaphragm and in the space surrounding the tube. For instance when themovement of the driven end 23 of the pumping unit I is toward its fixedend 22, the volume of the diaphragm space D1 decreases, and the rubbertube T1 is compressed radially by the water while its length is beingshortened by the movement of the driven end. Both effects reduce thevolume of the space inside the rubber tube T1. Conversely, when themovement of the driven end of the pumping unit is from its fixed end,the volume of the diaphragm unit is increased, and the rubber tube isexpandcd and at the same time elongated. Both actions increase thevolume of the space inside the rubber tube. It is seen that when thevolume of the space inside the tube T1 increases, fluid material inhopper 30 is drawn in through the inwardly opening check valve 67, whilethe valve 112 is held closed, and conversely, when the volume of thespace in the tube T1 decreases, the fluid material in the tube is forcedout through the outwardly opening check valve 112, while the intakevalve 67 is closed.

' Since the driven ends of the two pumping units I and II are joinedtogether, they are each subject to the same longitudinal displacement orstroke. However, the two pumping units are preferably so designed thatthe volume displacement of the first unit I is substantially twice thatof the second unit II. In the present embodiment, this result has beenaccomplished by making the effective piston area of the diaphragm D1substantially twice that of the effective piston area of the diaphragmD2, as has already been explained. It should be apparent, in thisregard, that the effective piston area depends almost entirely upon thediameter of the rigid internal diaphragmclamping and bracing rings, 96in the case of diaphragm D1 and 181 in the case of diaphragm D2, theactual effective area being slightly greater than the area of the rigidclamp rings. By making the former of substantially twice the area of thelatter, the diaphragm D1 has subsesame stantially twice the piston areaor volumetric displacement as the diaphragm D2. Pump I, thus providedwith twice the volumetric displacement of pump 11, pumps. substantiallytwice the volume of fluid as pump II on each stroke. It may be said thatthe action. of the diaphragm D1 is to pump two unit volumes of fluid oneach stroke, as compared with one unit volume for the diaphragm D2. Inoperation, the first pump unit I, on its expansion stroke, willtherefore fill itself with two units of volume of fluid from the hopper30 while the pump unit ll is discharging one unit of volume of fiuidthrough its discharge outlet. Conversely, while pump I is dischargingtwo units of volume of fluid into the pump ll durin its compression.stroke, pump II is filling itself with one unit of volume offluid,.while the remaining one unit of volume is discharged from thedischarge outlet. In this way, the pump assembly is made double acting,that is, one unit of volume of fluid is discharged from the systemduring the forward stroke and another during the return stroke.therefore discharges continuously.

The discharge rate tends to vary from minimum to maximum and then backto minimum during each stroke of the pump. The delivery rate from thepump is made much more uniform by the use of the spring-actuatedclamping members 190 engaged with the diaphragm D2 of the second pumpunit. The operation of the spring clamping means acting on the seconddiaphragm in smoothing out ripples in the discharge fromthe pump willnow be considered. At the outset, or in neutral position (Figure I thediaphragm D2 is slightly flattened owing to the pressure exerted bysprings 182 through plates 190. As the center section then moves towardthe left, the two-unit volume which is exhausted by pump unit I on eachleftward stroke is delivered into pump unit II. One unit volume isdelivered from pump unit II, and the other unit volume fills in theexpanded space owing to the expasion of. diaphragm DZ. At the mid-pointof this stroke, the diaphragm D2 is partially expanded owing toseparation of the adjacent ends of housing members 23' and 140', and inaddition, the pumping pressure then existing inside the diaphragm D2 issuflicient that said diaphragm has become somewhat further expandedagainst the springactuated clamping plates. This extra expansion issubtractive from the peak fluid delivery from the pump unit I'l. Then,at the end of the leftward stroke, as pump pressure and flow from pumpunit 1 tends to fall to its minimum, the spring-actuated clampingvplates 190 close in on' diaphragm D2, and delivery from the pump unit IIis thus kept up by the resulting volume reduction. of diaphragm D2.Correspondingly, on the rightward stroke, the diaphragm is somewhatexpanded against springs 182 in passing through the mid-portion of thestroke, subtracting from the flow rate, and somewhat contracted by thesprings at the end of the stroke, thus tending to keep the flow up whenit otherwise tends to slow or stop- The spring-actuated clamp on thediaphragm D2 thus causes the diaphragm to function as an accumulator, orfilter, smoothing out ripples inthe' flow from the pump by cutting downthe flow at the peaks and adding: to the flow at the depressions.

The pumping system as described in the foregoing is of a two stage, twocycle type, the two stages being phased 180 apart. As explained, thissystem discharges on each stroke, but the discharge is of a pulsatingcharacter. The pulsations are somewhat smoothed and reduced by use ofthe spring clamping device employed on the diaphragm member of thesecond stage, but the pulsating character of the discharge is still inevidence. Improvement in this regard is possible by addition of furtherstages, properly phased, and in- Figures 12 and 13 I havediagrammatically indicated a three phase version of pump in accordancewith the invention, the three stages of the pump operating with 120phase difference.

The pump diagrammed in Figure 12 will be understood as capable ofphysical embodiment in structures The pumping system as thus describedinvention.

similar to those explained. and illustrated hereinabove', as. will beunderstood by those skilled in the art. As only diagrammaticallyindicated in. Figure 12, therefore, the pump in this instance has threesuccessive stages 200, 201. and 202., wherein. is defined a longcontinuous conduit made up flexible, elastic tubes 203', 204' and 205',respectively. A. housingv for the first stage comprises housing parts206 and 207, connected by flexible diaphragmv 208,. and insimilarmanner, second stage housing comprises parts 209 and 210', connected bydiaphragm 21.1, while the third stage housing comprises parts 212' and213' connected by diaphragm 214'. The housing parts as described will.be understood to be connected in the above-described manner to the endsof the flexible tubes, and the adjacent ends of the housing members ofsuccessive stages. will be understood as connecting to one another, asin the embodiment previously described. An intake valve 215 is employedat the intake end of first. stage tube 203, and exhaust valve 216' isplaced at the discharge end of tube 203, this valve 216 being seen todischarge into the intake end of second stage tube 204. At the dischargeend of tube 204 is an exhaust valve 217', whose discharge is received bythe. intake end of tube 205- of third stage 202'.

Liquid chambers 218" are formed in the successive stages inside thehousing sections and. diaphragm and aroundthe outsides of. thesuccessive flexible tubes, as will be understood- The pumping system. asthus described is driven at two 0 points, first, at the junction of thefirst stage unit with the second, and second, at the junction of thesecond stage unit with the third. I have here indicated a suitabledriving means merely in a simple diagrammatic form, from which thoseskilled in the art will. readily understand. the As diagrammaticallyindicated, therefore, I. may employ, at each driving point, a slottedbar 225', projecting. laterally from. the interconnectedhousingportions, and receiving. a crank pin 226" carried by a crank disc 227',the two crank. discs being synchronized or interconnected with oneanother, as indicated conventionally by the dashed. line 228. Toaccomplish the desired phase relations, the second driving. point isdriven with 60 phase lagwith respect to thefirst. That is to say, andassuming for illustrative purposes that both crank discs are rotating ina clockwise direction, the crank pin which corresponds to the drivingpoint between. the'second and third pump stages has. a. phase lag of 60with respect to the crank. pin. corresponding to the driving pointbetween the first and second stages, as clearly illustrated in Figure12. It will become evident. as the description proceeds that the actualdirections of rotation of the cranks are immaterial, so long as thesecond crank pin has a 60 lag with respect to the first.

Figure 1-2. shows. the pump with the first stage fully contracted, thesecond. stage partially contracted, and the third stage partiallyexpanded, and for purposes of description, this will be taken. as thebeginning or 0 position of the cycle. Figure 13 shows, in diagram, thepositions of the three pump stages at 60 intervals throughout a full 360cycle. From an. inspection of this figure, and a comparison thereof withFigure 12,. it will. readily be apparent that the three stages 200',201" and202' are all gradually expanded and then contracted, but with120 of phase difference between successive stages.

As in the first-described. embodiment, the successive: stages arepreferably provided with decreasing volumetric displacements, in theratio of 3:2:1. That is to say, the diaphragm of first stage 200" isdesigned to pump three units of volume on each contraction, thediaphragm of stage 201 is designed to pump two units of volume on eachcontraction, and the diaphragm of stage 202' is designed to pump oneunit of volume on each contraction. Accordingly, during each contractionof stage 209, three units of volume are pumped into stage 201', and oneach contraction of stage 201', two units of volume are pumpedtherebyin'tostage 202-, while on each contraction of stage 202', one unit ofvolume is discharged therefrom. It will be evident that, as with thefirst-described embodiment, the stages 201 and 202, on their expansionstrokes, are incapable of retaining all of the material taken in, andthe excess is therefore discharged during the expansion stroke. In athree phase system such as diagrammed in Figures 12 and 13, this resultsin continuous discharge from the exhaust end of the third stage. Thereis of course still superimposed on this continuous discharge a certaindegree of ripple, but not sufllcicnt to be objectionable under ordinarycircumstances. Further improvement, of course, would result from use offurther stages in a multi-phase system, but it is believed that a threephase system is adequate for all practical purposes. Also, of course,spring clamping means employed on the second and third diaphragms, likethe device 182 of the first embodiment, may be employed, if desired, andwill function as an accumulator to further remove ripples from theoutflow. Such a device is indicated onthe third diaphragm in Figure 12,at 214.

The pumping of viscous, non-homogeneous semi-fluids such as plaster andstucco presents peculiar problems not found in the pumping of ordinaryliquids. The tendency of the mixture to separate and harden and formlumps in the pump and in the piping can lead to either stoppage ofpumping, or destruction of the pump. Since the material sets with timelike cement, it is evident that if at any point in the pump or piping astagnant pocket is formed, the material which first fills the pocketwill remain and eventually harden. Such deposits have a marked tendencyto grow larger or break loose as they impede the flow of material, andthey may eventually cut off the flow entirely or, if they form in orpass into that portion of the pump which undergoes volume change, theymay cause.

signed to have a small and substantially uniform cross sectionthroughout its lengh with a minimum of turns so that flow of materialthrough the pump is substantially equivalent to the flow in a straightpipe. If the cross section is small enough relative to the volume ofmaterial pumped, a positive forward flow will exist at all times at allpoints in the pump and no accumulation of material is possible. Thus, bycontinuous and complete purging of the system of all old material withfreshly prepared mixture, the tendency to harden in the pump is avoided.

Hardening and formation of lumps is also associated with the problem ofseparation. Practically all plasters and stuccos are a three phasesystem of fluid (usually water), binder (usually gypsum or cement), andan aggregate (usually sand or one of several types of less densematerial such as vermiculite). Such mixtures are purely mechanical andare unstable in the sense that an uneven distribution of the materialsis readily produced by the action of inertia forces, pressure gradients,or simple straining. These forces are effective because of differencesin density and viscosity of the material, and differences in size of thesolid particles.

When separation occurs between the liquid and the solid material, thelatter is no longer in a fluid state and packs into lumps and preventsfurther operation of the pump. A similar difiiculty takes place if thecoarser aggregates are separated from the more finely powdered cement orhinder. This is particularly true when the aggregate is ordinary sand,which. is much denser than the other components of the mixture. Asidefrom the inability of the pump to function when separation of thematerial takes place, the usefulness of the material as a plaster orstucco is greatly impaired thereby and it becomes useless if separationis at all pronounced.

. It is accordingly necessary to avoid the establishment of largeinertia forces or pressure gradients in the material, which enhanceseparation. The present pump isdesigned to operate at a low speed(typically R. P. M.) which permits the material to flow slowly andsmoothly into and through the pump. It has a large volume displacementrelative to its own internal volume which makes possible the combinationof large pumping rate with low operating speed and small internalvolume. V

This latter combination is of the utmost importance. Since most plastersand similar material are quite volume compressible due principally tothe inclusion of air, the necessity for a large volume change relativeto the internal volume, or in other words, a high compression ratio, isapparent in order to maintain a large volume flow against relativelyhigh back pressure. In actual practice, the pressure change through thepump is of the order of one hundred pounds per square inch, while thevolumetric etficiency, due to compressibility of the material, may be aslow as fifty per cent.

There are, then, a number of major features which a successful plasterpump should have. It should be self purging. It should pump the fluidwith a smooth, quiet flow. It should have a large compression ratio. Andit should be self priming. Combined with these are also the ability towithstand abrasion, and a means for obtaining a positive displacement inthe pump without having critical clearances. The present pump has beenshown to fully meet these various requirements.

It will be understood that the drawings and description are forillustrative purposes only, and that various changes in design,structure and arrangement may be made without departing from the spiritand scope of the appended claims.

I claim:

1. In a pump, the combination of: a flexible tube, an intake valve incommunication with one end of said tube, an exhaust valve incommunication with the other end of said tube, another flexible tubehaving one end in communication with said exhaust valve of saidfirst-mentioned tube, chamber means for each of said tubes for enclosinga hydraulic liquid body therearound, liquid displacing means for each ofsaid liquid bodies for accomplishing successive expansion andcontraction of the tubes, the liquid displacing means for the liquidbody around said firstmentioned tube having a greater volumetric liquiddisplacement perstroke than the liquid displacing means for the liquidbody around the second-mentioned tube, and means for actuating theliquid displacing means for the two tubes with a phase difference suchthat the expansion period for the second tube overlaps a substantialportion of the contraction period for the first tube, all in such mannerthat the liquid displacing means of larger volumetric displacement pumps.material from the first tube both into and through the second tubeduring the period of overlapping first tube contraction and second tubeexpansion.

2. A pump according to claim 1, wherein the phase difference between theliquid displacing means is substantially 3. The pump of claim 1 whereinat least one of said chambers comprises liquid body accumulator means tosmoothen ripples in the pump discharge. I

4. A pump according to claim 1, wherein the liquid displacing means forthe first liquid body has substantially twice the volumetric liquiddisplacement as the liquid displacing means for the second liquid body.

5. A pump according the claim 4, wherein the phase difference betweenthe liquid displacing means is substantially 180.

6. In a pump, the combination of: a flexible tube, an intake valve incommunication with an intake end of said tube, an exhaust valve incommunication with an exhaust end of said tube, another flexible tube,said second-mentioned tube having an intake end communicating with 3said exhaust valve of said first-mentioned tube, chamber.

means for each of said tubes for enclosing a liquid body therearound,and a contracting and expanding means for each of said tubes havingoperative connection with opposite ends of the tube and operable to movesaid ends toward and from one another to alternately longitudinallyexpand said tube and permit it to longitudinally contract, saidcontracting and expanding means including. also liquid displacing meansfor elevating and-reducing the hydraulic pressure on the liquid bodysurrounding the associated tube in step with movement of said tube endstoward and from one another.

7. The pump of claim 6, wherein the contracting and expanding means forthe tubes are interconnected to operate with a substantial phasedifference.

8. The pump of claim 6, wherein the contracting and expanding means forthe twotubes are interconnected to operate with a phase difference of180 9'. The pump of claim 6, wherein the liquid displacing means for theliquid body surrounding the first tube has a substantially greatervolumetric displacement than the liquid displacing means for the liquidbody surrounding the second tube.

10. The pump of claim 6-, wherein the liquid displacing means for theliquid body surrounding the first tube has substantially double thevolumetric displacement of the liquid displacing means for the liquidbody surrounding the second tube.

11. The pump of claim 9, wherein. the liquid displacing. means for theliquid body surrounding the first tube has substantially double thevolumetric displacement of the liquid displacing means for the liquidbody surrounding the second tube.

12. In a pump, the combination of: a flexible tube,

clamping and sealing means at both ends of said tube for clamping saidtube and sealing therearound at both its ends, an intake valvecommunicating with one end of said tube, an exhaust valve communicatingwith the opposite end of said tube, a longitudinally expansive andcontractive housing surrounding said tube and joining said clamping andsealing means at the two ends of the tube, there being a space to befilled by a liquid body inside said housing and around the outside ofsaid tube, and means for alternately longitudinally contracting andexpanding said housing, whereby to alternately contract said tube in alongitudinal direction and simultaneously contract the same laterally byexternal liquid pressure compression, and elongate said tubelongitudinally and simultaneously allow it to expand laterally byreduction of the external liquid pressure.

13. in a pump, the combination of: a tube made of flexible materialimpervious to the fluid being pumped; an inlet valve in communicationwith one end of said tube and an outlet valve in communication with theother end of said tube; a housing enclosing the outer side walls of saidflexible tube, said housing including a diaphragm; a relativelyincompressible fluid completely filling the space between the outerwalls of said tube and the inner walls of said housing and saiddiaphragm; and means for alternately applying and releasing pressure tosaid diaphragm whereby a hydraulic pressure is transmitted by said fluidto the outer walls of said flexible tube and said tube is alternatelycompressed and expanded and its internal volume is alternately decreasedand increased thereby and the fluid to be pumped is drawn in throughsaid inlet valve and discharged from said outlet valve.

14. In a pump, the combination of: a tube made of flexible materialimpervious to the fluid being pumped; an inlet valve at one end of saidtube and a discharge valve at the other end of said tube; a housingenclosing the outer side walls of said elastic tube, said housing beingattached to the ends of said tube and including a diaphragm which ismovable in a line parallel to the length axis of said tube and whichproduces a change in the volume enclosed by said diaphragm and housingwhen moved along said line; a relatively incompressible fluid completelyfilling 14 the space between the housing and the outer walls of the saidtube; means for moving said valves relative to'each other in areciprocating motion in a line parallel to the length axis of said tubewhereby said tube is alternately stretched and relaxed andsimultaneously said diaphragm associated with said housing. is moved toalternately change the volume enclosed by said housing and the outerwalls of said tube, whereby the tube is subjected to hydraulic pressurewhen said tube is relaxed, and said hydraulic pressure is released whensaid tube is stretched, causing the internal volume of said tube to bealternately increased and decreased due both to elongation and expandingand by relaxing and compressing, and fluid is.

caused to flow into said tube through said inlet valve and to bedischarged through. said outlet valve because of the alternating volumechange in said tube.

15. In a pump, the combination of: a flexible tube, clamping and sealingmeans at bothends of said tubefor clamping said tube and sealingtherearound at'both its ends, an intake valve communicating with. oneend of relatively moving said housing parts toward and from one anotheralong said axis.

16. The subject matter of claim 15, wherein said diaphragm issubstantially U-shaped in cross section, with its two top portionsconnected to the two housing parts.

17. In a pump, the combination of: first and second flexible tubes,clamping and sealing means at both ends of each of said tubes forclamping said tubes and sealing therearound at both ends thereof, anintake valve communicating with an intake end of said first tube, anexhaust valve communicating With the opposite end of said first tube, anintake end of said second tube connected to reccive the discharge fromsaid exhaust valve, 21 housing structure around each of said tubescomprising two housing parts movable toward and from one another alongthe axis of the associated tube, said housing parts being sealinglyjoined and operatively connected to the clamping and sealing means atthe two ends of the associated tube, flexible diaphragms joining the twoparts of each of said housing structures and functioning therewith toform expansive and contractive liquid chambers around said flexibletubes, and driving means for moving the two housing parts of saidhousing structures alternately toward and from one another.

18. The subject matter of claim 17, wherein said driving means isarranged to move the two housing parts of one housing structure towardone another while moving the two housing parts of the other apart, andvice versa, whereby to accomplish oppositely phased expansion andcontraction of the two liquid chambers.

19. The subject matter of claim 18, wherein the eifective liquiddisplacing area of the diaphragm associated with the first tube issubstantially twice that of the diaphragm associated with the secondtube.

20. In a pump, the combination of: first and second axially alignedflexible tubes, said tubes each having an intake end and a dischargeend, the tubes being arranged with the discharge end of the first tubeadjacent the intake end of the second tube, connecting means operativelyinterconnecting the discharge end of the first tube with the intake endof the second tube, an intake valve at the intake end of the first tube,a discharge valve at the discharge end of the first tube, said dischargevalve arranged to discharge into the intake end of the second tube,housing means for each of the tubes 'including two separate housingparts, one connected and sealed to each end of the respective tube,means stationarily mounting the housing parts connected to the intakeend of the first tube and the discharge end of the second tube, theremaining housing parts being joined to said connecting means, aflexible diaphragm connecting the two housing parts of each of saidhousing means, so as to form therewith a liquid chamber surrounding thetube, and driving means operatively connected with said connecting meansfor reciprocating said connecting means and the housing parts joinedthereto along the axis of the tubes, in such manner that said diaphragmsand liquid chambers are expanded and contracted in opposite phase.

21. The subject matter of claim 20, wherein the effective liquiddisplacing area of the diaphragm associated with the first tube issubstantially twice that of the diaphragm associated with the secondtube. V

22. In a pump, the combination of three axially aligned flexible tubesconnected end to end in a series arrangement, a two-part tubular housingmeans for each tube and a flexible diaphragm for each housing connectingsaid two parts thereof for relative movement toward and from one anotheralong the axis of the tubes, one part of each such housing means beingconnected to one end of the associated tube and the other to the otherend of said tube, the housing parts corresponding with confronting endsof successive tubes being interconnected with one another forcorresponding movement,v and the remaining housing parts, correspondingwith therintake end of the first tube and the discharge end of the thirdtube, being stationarily mounted, said housing means and diaphragmsforming liquid chambers surrounding the tubes, an intake valve openingto the intake end of the first tube, said valve being connected to thestationarily mounted housing part for the first tube, a valve at thejuncture of the first and second tubes connected to the interconnectedhousing parts of the first and second tubes and serving as a dischargevalve for the first tube and an intake valve for the second tube, avalve at the juncture of the second and third tubes connected to theinterconnected housing parts of the second and third tubes and servingas a discharge valve for the second tube and as an intake valve for thethird tube, and driving means operatively connected with theinterconnected housing parts of the first and second tubes and with theinterconnected housing parts of the second and third tubes forreciprocating said interconnected housing parts along the axis of saidtubes, with said interconnected housing parts of the second and thirdtubes lagging the interconnected housing parts of the first and secondtubes by a phase angle of substantially References Cited in the file ofthis patent UNITED STATES PATENTS 2,046,491 Scott July 7, 1936 2,291,912Meyers Aug. 4, 1942 2,626,569 Knudson Jan. 27, 1953 FOREIGN PATENTS287,267 Great Britain Mar. 22, 1928 641,453 France Apr. 16, 1928

